An open labial stop, of 16 ft. pitch, the pipes of which are of wood,
quadrangular in form, and mouthed and voiced similar to those of the
Hohlflöte (q.v.). It
furnishes the proper bass to the manual unison stop, and is,
accordingly, a Pedal Organ stop; but rarely introduced in modern
Organs.

In The Art of Organ-Building Audsley lists
Hohlflötenbass,
as being synonymous with
Grosshohlflöte
but lists them separately in his later work
Organ-Stops and their Artistic Registration.

The suffix bass is used with some consistency by German
organ builders to indicate that a stop belongs to the pedal
division, and does not necessarily imply a lower pitch.